Heavy filled material such as fluids filled with granules to simulate granite or marble surfaces are used for coating various products. However a problem with these materials is delivering them to the product to be coated. There are pumps which will pump such materials but applying them to the product is difficult because attempts to spray the materials cause "packing-out." Packing-out is the phenomenon of the heavy components in the materials separating when the material is under static back pressure that can cause clogging of passageways stopping the flow. Typically the loading ratio of these heavy filled fluid materials is 45% solids or granules to 55% fluid or greater.
Presently there are no efficient spraying devices for applying such heavy filled materials. Most methods of applying such materials are by pouring or some other method of manually applying the material to a surface. However this type of application is inefficient and not completely satisfactory as the finished surfaces can be uneven and unattractive. When using heavy filled materials to simulate marbling type surfaces the user desires to provide a smooth non-abrasive surface. The present methods of applying these products make producing such surfaces difficult.
It is one object of the invention to provide a plural component spray gun for a heavy filled primary fluid material that automatically recirculates the primary fluid to control and minimize static back pressure to prevent clogging of the spray nozzle and passageways.
It is also an object of the present invention to provide a pumping and plural component spray system which can efficiently deliver heavy filled fluid materials.
Yet another object of the present invention is to provide a pumping and spraying system that can deliver heavy filled materials at relatively low pressures.
Still another object of the present invention is to provide a pumping and spraying system that prevents the material from "packing-out" and clogging the equipment.
Still another object of the present invention is to provide a system for pumping and spraying heavy filled materials that has an automatic recirculation mode at the gun nozzle that keeps the material moving to prevent clogging of fluid passageways in the spray gun.
Still another object of the present invention is to provide a pumping and spraying system for heavy filled materials that employs a divergent conduit to prevent static pressure and keep heavy filled material moving.
Yet another object of the present invention is to provide a pumping and spraying system that supplies heavy filled primary fluid material on demand without any lead or lag times between the primary and secondary fluids.
Yet another object is to provide a pump and spraying system for granite effect gel coat material or the like in which the resin is heavily loaded and the particles are large.